I am trying to run -current off of an USB stick on my eeepc900, in order
to build some confidence in it before wiping the SSD, and I am seeing
weird behaviour that I can't explain:
After a kernel panic[0] in the middle of a bulk-install of large amounts
of bloat[1], I thought the state of my pkg tree seemed a bit too messed up
for having been caused by that panic alone, so I pkg_admin check'd my
entire tree -- and it complained about a whole lot of MD5 mismatches.

Are you copying software to the eeepc over ethernet or WLAN?

PIII build-box (ex0) -> LAN switch -> eeepc (lii0)

Can you try copying with scp?

It's worth a try. Speaking of network and NFS, I got (apart from those
"ex0: transmit underrun" messages) abysmal NFS performance when backing
stuff up on the DELL box before installing -current on it; on the order of
200kB/s, 100Mbit switched network, to my main workstation running 4.0.

Perhaps that ex0 is simply fishy...

and with all the checksumming going on in the network layers it
seems unlikely the bit errors would have come from there.

It is unlikely, but it is not impossible.

Scary if I can't trust my network. That would open up an ugly can of data
integrity worms.. :-S